Smoke projectile with delay fuse



April 23, 1957 H. RosENTHAL 2,789,467'

SMOKE PROJECTILE WITH DELAY FUSE IIWENTOR;v

Henry Rngenlhal April 23,' 1957 H. Rosi-:NTHAL 2,789,457

j sMoxE PROJECTILE WITH DELAY FUSE Filed May 22,1 1952'V 1 2 sheets-sheet 2 INVENTOR. 11i-hal.

Henri; Ruse SMOKE PROIECTILE WITH DELAY FUSE Henry Rosenthal, Crestwood, N. Y., assignor to the United States of America as represented by the Secretary of the Army Application May 22, 1952, Serial No. 289,420 Claims. (Cl. 89-1) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described in the specification and claims may be manufactured by or for the Government for governmental purposes without the payment to me of any royalty thereon.

The present invention relates to a smoke projectile. More particularly the present invention relates to a smoke projectile to provide smoke cover for a combat vehicle for any maneuver in which the vehicle may be participating.

VPrevious smoke grenades developed to provide a quick get away for combat vehicles, and to insure suiiicient smoke protection during maneuvering were found to be inadequate for screening purposes, due to the excessive time required for the projectile to produce the desired volume of smoke.

It is accordingly an object of this invention to provide a smoke projectile which establishes an eiective smoke screen within a very short time interval after initiation of the charge.

It is also another object of this invention to provide a smoke projectile in which means to detonate the propellaut charge, and a delay fuse to initiate the smoke charge, are series connected to be simultaneously set oi by a remote control tiring switch located within the safe confines of the combat vehicle.

It is still another object of this invention to provide a smoke projectile which is simple in construction, light in weight, easy to assemble, and easy to load in a projector or launching tube.

With these and other objects in view which will become apparent as the following speciiication develops, reference is made to the accompanying drawing wherein:

Figure 1 is a view in elevation of the smoke projectile in place in a launching tube. Y

Figure 2 is a fragmentary detail of the lower end of the launching tube and smoke projectile, including the wiring connections from a power source to the propellant squib and delay fuse.

Figure 3 is a transverse section taken on line 3-3 of Figure 2.

Figure 4 is an exploded longitudinal view of the smoke projectile showing details of assembly.

Figure 5 is a section taken on line 5-5 of Figure 1 with the smoke projectile removed.

The smoke grenade per se consists of a canister for receiving a smoke producing charge of white phosphorus and steel wool and a bursting charge, and a propelling charge case for receiving an igniter and a propellant charge. Referring more particularly to Figure 4 the grenade canister 1 is a cup shaped thin-walled steel member having a downwardly depending wall 2. The top wall of the canister is provided with a metal tab 3 which may be bent out and used as a handle to pull the grenade free of the launcher, if necessary.. The lower open end of the canister 1 is provided with a c losure plug 4 which is a heavy-walled metal member having its circumferential edge turned upwardly through 90 to form a short leg 5 for peripherally engaging the limer nited States Patent Patented Apr. 23, 1957 ICC' wall of canister 1 adjacent its lower edge as at 6. Leg 5 is secured in any convenient manner, as by welding or brazing, to canister 1. The central portion of closure 4 is blanked out to form an aperture 7, dened by a vertically upstanding reentrant leg S of the closure plug, for receiving the burster well assembly 9.

The burster well assembly comprises a cupshaped, elongated, thin walled steel well member 10 approximately one half the height of canister 1 and of a diameter smaller than aperture 7, and a heavy walled sleeve member 11 which is provided with an upper reduced portion 12a, the inner surface of which peripherally engages, as at 12, and is secured to the outer wall of well member 10 adjacent its lower edge. In assembling the smoke grenade, well member 10 and sleeve member 11 are inserted into aperture 7 so that the burster well assembly extends into canister 1. The outer diameter of sleeve member 11 is the same as the diameter of aperture 7 so that a snug, tight t is provided between reentrant leg portion S of closure plug 4 and the outer peripheral surface of sleeve 11, wherefore a smoke producing agent 13a such as white phosphorus and steel wool, or any similar substance having pyrophoric properties, placed in canister 1, is prevented from spilling out.

The propelling charge case assembly comprises a lid 13 which is formed `as a shallow downwardly depending cup member with a plurality of grooves 14 formed in the vertical wall thereof and extending iirst upwardly and then circumferentially to provide the Well known interrupted bayonet type thread. The at upper surface 15 of lid 13 is centrally apertured, as at 15a, for fixedly receiving an upwardly extending externally threaded plug 16, which in turn is provided with an internally threaded bore 17 for screw threadedly receiving a bushing 18. The inner wall of burster sleeve 11 is provided with threads 11a to mate with the external threads on plug 16 when the parts are assembled, and after the upper portion of bursting charge container 19 is received in the upwardly extending well 10, and the lower portion in bushing 18 (see Fig. 2). The bursting charge 52 is a delay, special booster type electrical detonator having a high explosive of sufficient intensity to fracture and explode both the burster well and canister. When the burster charge is detonated, the burster well and canister are fragmentized to expose the white phosphorus to atmosphere, whereupon it ignites spontaneously to produce smoke. The propellant container is an annular cup shaped member 20 having an upwardly extending wall 21, and a bottom wall 22 provided with an upwardly extending reentrant portion 23 to form a recess 24, having an upper at wall 24a, for receiving parts ot the electrical connection subsequently to be described. The upper edge of wall 21 is provided, externally thereof, with a plurality of equiangularly spaced lugs 21a equal in number to the bayonet grooves and cooperating therewith to provide a secure latching means, when the lugs are inserted into the bayonet grooves and after cup member 20 is given a slight twist, as is well known. The propellant in cup member 2t) comprises a toroidally shaped main charge 25 (see Fig. 2) encased in long paper cartridge which encircles the upright wall of recess 24, and a smaller vented electrical squib 26 which is made to adhere to the main propellant, and which when electrically ignited sets off the main propellant charge to eject the smoke projectile from the tube Z7 of a launcher or projector. The lowermost wall of cup member 20 is provided with a plurality of gas exhaust ports 28, as plainly seen in Figures 3 and 4.

The projector or launcher consists of a battery of six launching tubes (one only shown), a pulser assembly (not shown), and control switches (not shown). Re-

ferring more particularly to Figures l and 2 the tube 27 is an elongated, comparatively heavy walled metal cylinder provided, adjacent its lower edge with a cylindrical recess or shoulder 29 onto which is fitted a base plate 36, and which is secured to the combat vehicle frame 31 bymeans of a plurality of socket screws (not shown). The base plate 30 is centrally apertured, as at 33, to receive an elongated, upwardly extending contact plug 34, which is insulatingly separated from plate 30 by virtue of a collar 35 of suitable dielectric material. The lower end of plug 34 is threaded and provided with nuts 34a which are used to connect plug 34 with one end of a wire 36, extending to one side of a power source 37.

Three double duty leaf springs 38, are secured as at 39 to the upper face of base plate Sil, and are provided with upwardly extending curved resilient fingers 40 for grasping the Vouter peripheral surface of propellant cup member 20, and to make ground contact with the propelling charge case. To complete the electrical connection, top wall 24a of cup member 2?, is centrally apertured as at 4l for receiving a screw and nut assembly 42, insuiatingly spaced from the propellant case by dielectric bushing 42a, to secure to the under side of wall 24a, a downwardly extending U-shaped spring clip 43 with reversely curved ends 44, To the upper end of screw and nut assembly 42, is secured one end of an electrical wire 45, which extends through a central aperture itin in plug 16 to make a first connection 46 with the delay fuse in the burster charge, and a series connection 47 with the propellant squib. Lead 47a provides a ground connection between the squib and propellant case. Base plate 3ft is provided with a screw and nut connection 48 to which is secured a lead 49 which is connected to the other side of the power source 37 to complete the circuit. A main re control switch is also provided in the circuit which is hand actuated to olf the smoke projectile when it is in place in the launching tube.

The assembly of the smoke projectile will be apparent from the above description. The projectile is loaded into the muzzle end of the launcher tube with the propellant case end first, and the resilient fingers 4t? are so located that `they readily make contact with and grasp the propellant case when the required pressure is applied to the top end of the canister. A plurality of stops 32 secured as by rivets to the upper surface of base plate 30, make contact with the bottom surface of the propellant case to vertically position the smoke projectile in the launching tube. As these stop rivets pass through apertures in spring 38, they also assist in securing the latter to the plate. When the projectile is in the tube, plug 34 and spring clip 43 are in vertical alinement, and the upper end of plug 34 is forced into and is grasped by curved ends 44 of the clip to make the necessary connection to Athe firing circuit. A launching tube cover 5l is then forced over the end of each launching tube to keep out moisture and dirt. Cover 5l is a dish-shaped member having a downwardly depending side wall outwardly curved reversely through 189 as at 51a, and then curved reversely again through 180 as at 53 to form a resilient loop for receiving 'the upper end of the launching tube 27, The extreme peripheral end of the cover is then curved first inwardly and upwardly at 4- to form a resilient member adapted to be forced into an annular recess 55 formed in the outer surface of tube 27 adjacent the upper end thereof. A bow spring 56 is riveted to 'the under side of cover 5l adapted to have its spreading legs press against the top of the smoke projectile to maintain the projectile within resilient fingers 4t! and in contact with stops 32.

Preparatory to loading the projectile into the tube all necessary precautions must be `taken to see that a safety connecting plug in the instrument panel (not shown) is disconnected 'and the main fire control switch is turned off. When the vehicle is in safe location for firing and when its hatches are closed, the plug on the instrument panel s first connected, and then the firing switch is closed. Simultaneously the propellant and the delay fuse are ignited, and according to tests, an effective smoke screen is established within a maximum of five seconds after initiation. This smoke :screen will persist for at least 2 minutes, providing ample time for maneuvering to safe position, and' for a quick get away.

Numerous other modifications and alterations of the structure which has been disclosed herein for purposes of illustration will be apparent to one skilled in the art, and it is obvious that the same may be made without departing from the Spirit and scope of the invention as defined in the following claims.

I claim:

1. Asmoke'projectile comprising a canister having a centrally apertured bottom wall, a closure plug for said aperture, said closure plugcomprising a hollow elongated sleeve extending axially into said canister and having a closed upper end forming a well to receive a burster charge, -said burster chargeV having associated therewith a delay train fuse, a pyrophoric smoke producing agent in said canister, a lid for said burster charge well, said lid comprising a flat plate, an upwardly extending boss secured tothe upper surface of said at plate having external threads to screw-threadedly mate with threads formed on the inner surface of said hollow sleeve adjacent its lower end, and a downwardly depending circumferential wall secured to the lower surface of said flat plate, said wall having formed therein a plurality of bayonet threads, an annular propellant case having a circular horizontalV plate peripherally joining and integral with the upper edge of the inner wall forming said annular case, a toroidal propelling charge in said propellant case, a squib in said case for detonating said propellant charge, and circuit `means series connecting said delay train and said fuse, including a power source consisting of a contact plug extending through a hole in the closed end of said tube adapted to be releasably engaged by U-shaped spring-clip members having reversely curved ends extending downwardly from said lid and hand operated switch mounted externally of said propellant case, for simultaneously initiating said propellant charge and said burster charge.

2. In combination with a tubular launcher having a closed end, a smoke projectile adapted to be propelled from said launcher tube and comprising, a canister having a centrally apertured bottom wall, a closure plug for said aperture and having a hollow elongated sleeve extending axially into said canister, said plug having a closed upper end forming a well to receive a burster charge including a delay train `fuse therefor, a pyrophoric smoke producing agent in said canister, a lid for said burster charge well, said lid comprising a flat plate, an upwardly extending boss secured to the upper surface of said flat plate and having external threads to screw-threadedly Ymate with threads formed on said hollow sleeve adjacent its lower end, and a downwardly depending circumferential wall secured to the lower surface of said flat plate, said wall having formed therein a plurality of bayonet threads, an annular propellant case having a circular horizontal plate peripherally secured to upper edge of the inner wall Vforming said'annular case, a toroidal propelling charge in said propellant case, a squib in said case for detonating said propellant charge, a plurality of inwardly extending resilient `fingers secured to the inner surface if the closed end of said launcher tube for releasably engaging said propellant case, and power means externally ofV said closed end comprising downwardly extending U-shaped spring-clip members having reversely curved ends adapted to receive and to make electrical Contact with an upwardly extending member protruding through said flat plate and including circuit means extending through said closed end for series connecting said propellant initiating means and said delay train.

3, In combination with a smoke projectile launcher comprising an elongated cylindrical tube having a closed end; a canister within said tube, a pyrophoric smoke producing agent within said canister, means including a delay train fuse within said canister detonatable to fragmentize said canister comprising a cup-shaped well member secured to the inner surface of the bottom of said canister, a burster charge in said well member, a delay train in said well member adapted to detonate said burster charge; means including a bayonet joint for releasably securing said cup-shaped member to the bottom of said canister comprising a plurality of resilient ngers secured to the inner surface of said closed end and extending inwardly into said tube to grasp said cup-shaped member, a propellant received within said cup-shaped member, a squib within said cup-shaped member adapted to initiate said propellant charge, a ring circuit comprising a contact plug extending through a hole in the closed end of said tube and insulatingly separated from said closed end, means extending through the bottom of said cup-shaped member comprising downwardly extending U-shaped spring-clip members having reversely curved ends releasably engaging said contact plug to make electrical contact therewith, a lead extending through the bottom of said canister connecting said contact plug engaging means successively with said squib and said delay train, and a hand operated re control switch in said circuit externally of said launcher tube for simultaneously igniting said squib and said delay train.

4. In combination with a smoke projectile launcher comprising an elongated cylindrical tube having a closed end, a canister within said tube, a smoke-producing agent within said canister, a cup-shaped well member secured to the bottom wall of said canister and extending axially inwardly of said canister, a burster charge having a delay fuse received within said well, a propellant case, means secured to said closed end releasably engaging said propellant case to the outer surface of the bottom of said canister comprising a plurality of resilient fingers secured to the inner surface of said closed end, a propellant charge in said case means to initiate said propellant charge, a power source external of said launcher tube, electrical conduit means comprising a contact plug extending through a hole in the closed end of said tube and insulatingly separated from said closed end, means extending through the bottom of said propellant case comprising downwardly extending U-shaped spring-clip members having reversely curved ends releasably engaging said contact plug to make electrical contact therewith, a lead extending through an aperture in the bottom of said canister connecting said contact plug engaging means successively with said squib and said delay train, said electrical conduit means series connecting said delay fuse and said initiating means with said power source, and a tire control switch in said electrical conduit means.

5. In combination with a tubular launcher having one end closed, a smoke projectile adapted to be propelled from said launcher tube, said smoke projectile comprising a canister, a smoke producing agent within said canister, a cup-shaped well member extending axially inwardly of said canister and secured thereto, a burster charge having an electrically ignited delay fuse received within said well, a propellant case secured to the outer surface of the lower end of said canister, an electrically ignited propellant charge in said case, an electric igniter circuit series connecting said fuse and said propellant charge, said circuit including electric switch means and power source externally of said launcher and an electric contact comprising a U-shaped clip secured to the lower end of said canister and removably connected to an upwardly extending member protruding through the closed end of said launcher.

References Cited in the le of this patent UNITED STATES PATENTS 950,956 Reed Mar. 1, 1910 1,687,159 Gammeter Oct. 9, 1928 1,937,191 `Driggs Nov. 28, 1933 1,947,834 Driggs et al Feb. 20, 1934 2,315,753 Long Apr. 6, 1943 2,340,047 Dunn Jan. 25, 1944 2,459,687 Decker Jan. 18, 1949 2,459,833 McLain et al. Jan. 25, 1949 2,459,854 Swift Jan. 25, 1949 FOREIGN PATENTS V660,225 Great Britain Oct. 3l, 1951 

